1. Technical Field
The present invention relates to a method and device for automatic de-misting and de-icing, using what is typically referred to as a defroster, a surface, for example a window, and particularly windows in automobiles.
2. Background Art
A common way of regulating the passenger compartment temperature in a car is to use so-called automatic climate control, a function that generates control signals for a number of different functions in the car. An example is found in the built-in air-conditioning system of an automobile in which the desired passenger compartment temperature is automatically maintained.
A further aim of automatic climate control can be to ensure that the car windows, primarily the windscreen, are kept free of mist, thereby establishing a so-called defroster function. For this purpose, the automatic climate control ensures that dry and warm air is directed at the windscreen. Since the climate control system does not know whether the windscreen is misted up or not, this will occur irrespective of whether or not it is required. Since the control, heating and cooling of air are activities and operations that require energy, fuel consumption consequently also increases irrespective of whether or not conditions actually exist that would require the defrosting function. Some of the adjustments which are made by know automatic climate control arrangements, in order to achieve the desired passenger compartment temperature, can actually run counter to the objective of achieving optimum demisting.
If the windscreen is completely or partially covered with ice, possibly in combination with mist, the climate control system will perhaps be unable to direct sufficient amounts of dry and warm air at the windscreen, in which case the driver has to take some course of action, for example press a button to activate the desired demisting function. This applies, for example, in cases where the windscreen has suddenly iced over as a result of driving into a cold environment.
Sensors that detect the presence of mist or ice on a surface such as a car window are known and can function according to a number of different principles; for example, by optical detection or by detection of air moisture content. The use of this information from such a sensor is, however, not known in conjunction with a climate control system in a car in ways that give optimum and automatic demisting.
One goal of the present invention is to use information from a sensor for detecting the presence of mist or ice on a surface, for example a car window, and, with the aid of a system for climate control or temperature regulation in the car, to achieve optimum automatic demisting, defroster function, on the surface.
The invention utilizes the aid of a device in an automatic defrosting function for a surface in a car; typically the windscreen or other window. The device exemplarily includes a sensor for detecting the presence of mist or ice on the surface of interest. A means, preferably in the form of an information processing unit, is utilized for generating control signals on the basis of the mist sensor data for a number of functions in the car, including optimizing the defroster function on the observed surface. A means is also included for receiving these control signals. The device further includes means for receiving control signals for a number of functions in the car from a function for temperature regulation.
In the arrangement, some of the control signals from the temperature regulator are intended to control the same functions in the car as the control signals for the optimum defroster function, and the same means are also used for receiving control signals for optimum defroster function and for receiving a number of the corresponding control signals from the temperature regulator. The means for receiving control signals are intended, in the event of conflict, to select those control signals that are designed to give the best demisting. This ensures that an automatic and efficient defroster function can at all times be achieved using an arrangement according to the invention, as well as the methods indicated thereby. The fact that the selected control signals are the ones that produce the greatest demisting means that when the function for optimum defrosting has generated a control signal giving less defrosting than the temperature regulator, the control signal from the temperature regulator is selected.
Since the invention provides the possibility of selecting which of the control signals from the temperature regulator are connected to the same means as the control signals for the defroster function, it is possible to determine which of the control signals from the temperature regulator will be included in this selection.
The means for generating control signals for an optimum defroster function preferably also include means for storing and reading off the values for the functions of the respective control signals, where the stored values give the optimum defroster function for certain input data from the sensor for detecting the presence of mist or ice. In this way, suitable or optimum values for the respective functions for different input data from the mist sensor can be calculated or tested out and stored in advance and then used as, and when required.